/**
 * @file
 * Ethernet Interface for standalone applications (without RTOS) - works only for
 * ethernet polling mode (polling for ethernet frame reception)
 *
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

#include "lwip/mem.h"
#include "netif/etharp.h"
#include "ethernetif.h"
#include "stm32f4x7_eth.h"
#include "main.h"
#include <string.h>
#include "netconf.h"

/* Network interface name */
#define IFNAME0 'e'
#define IFNAME1 'n'
volatile char DTUName[18];

/* Ethernet Rx & Tx DMA Descriptors */
extern ETH_DMADESCTypeDef  DMARxDscrTab[ETH_RXBUFNB], DMATxDscrTab[ETH_TXBUFNB];

/* Ethernet Driver Receive buffers  */
extern uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE];

/* Ethernet Driver Transmit buffers */
extern uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE];

/* Global pointers to track current transmit and receive descriptors */
extern ETH_DMADESCTypeDef  *DMATxDescToSet;
extern ETH_DMADESCTypeDef  *DMARxDescToGet;

/* Global pointer for last received frame infos */
extern ETH_DMA_Rx_Frame_infos *DMA_RX_FRAME_infos;




/**
 * In this function, the hardware should be initialized.
 * Called from ethernetif_init().
 *
 * @param netif the already initialized lwip network interface structure
 *        for this ethernetif
 */
static void low_level_init(struct netif *netif)
{
#ifdef CHECKSUM_BY_HARDWARE
    int i;
#endif
    /* set MAC hardware address length */
    netif->hwaddr_len = ETHARP_HWADDR_LEN;
    /* set MAC hardware address */
    netif->hwaddr[0] =  MAC_ADDR[0];
    netif->hwaddr[1] =  MAC_ADDR[1];
    netif->hwaddr[2] =  MAC_ADDR[2];
    netif->hwaddr[3] =  MAC_ADDR[3];
    netif->hwaddr[4] =  MAC_ADDR[4];
    netif->hwaddr[5] =  MAC_ADDR[5];
    /* initialize MAC address in ethernet MAC */
    ETH_MACAddressConfig(ETH_MAC_Address0, netif->hwaddr);
    /* maximum transfer unit */
    netif->mtu = 1500;
    /* device capabilities */
    /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
    netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
    /* Initialize Tx Descriptors list: Chain Mode */
    ETH_DMATxDescChainInit(DMATxDscrTab, &Tx_Buff[0][0], ETH_TXBUFNB);
    /* Initialize Rx Descriptors list: Chain Mode  */
    ETH_DMARxDescChainInit(DMARxDscrTab, &Rx_Buff[0][0], ETH_RXBUFNB);
#ifdef CHECKSUM_BY_HARDWARE

    /* Enable the TCP, UDP and ICMP checksum insertion for the Tx frames */
    for(i = 0; i < ETH_TXBUFNB; i++)
    {
        ETH_DMATxDescChecksumInsertionConfig(&DMATxDscrTab[i], ETH_DMATxDesc_ChecksumTCPUDPICMPFull);
    }

#endif
    /* Note: TCP, UDP, ICMP checksum checking for received frame are enabled in DMA config */
    /* Enable MAC and DMA transmission and reception */
    ETH_Start();
}

/**
 * This function should do the actual transmission of the packet. The packet is
 * contained in the pbuf that is passed to the function. This pbuf
 * might be chained.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 * @return ERR_OK if the packet could be sent
 *         an err_t value if the packet couldn't be sent
 *
 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
 *       strange results. You might consider waiting for space in the DMA queue
 *       to become availale since the stack doesn't retry to send a packet
 *       dropped because of memory failure (except for the TCP timers).
 */

static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
    struct pbuf *q;
    int framelength = 0;
    u8 *buffer = (u8 *)(DMATxDescToSet->Buffer1Addr);

    /* copy frame from pbufs to driver buffers */
    for(q = p; q != NULL; q = q->next)
    {
        memcpy((u8_t *)&buffer[framelength], q->payload, q->len);
        framelength = framelength + q->len;
    }

    /* Note: padding and CRC for transmitted frame
       are automatically inserted by DMA */
    /* Prepare transmit descriptors to give to DMA*/
    ETH_Prepare_Transmit_Descriptors(framelength);
    return ERR_OK;
}

/**
 * Should allocate a pbuf and transfer the bytes of the incoming
 * packet from the interface into the pbuf.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return a pbuf filled with the received packet (including MAC header)
 *         NULL on memory error
 */
static struct pbuf *low_level_input(struct netif *netif)
{
    struct pbuf *p, *q;
    u16_t len;
    int l = 0;
    FrameTypeDef frame;
    u8 *buffer;
    uint32_t i = 0;
    __IO ETH_DMADESCTypeDef *DMARxNextDesc;
    p = NULL;
    /* get received frame */
    frame = ETH_Get_Received_Frame();
    /* Obtain the size of the packet and put it into the "len" variable. */
    len = frame.length;
    buffer = (u8 *)frame.buffer;
    /* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
    p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

    /* copy received frame to pbuf chain */
    if(p != NULL)
    {
        for(q = p; q != NULL; q = q->next)
        {
            memcpy((u8_t *)q->payload, (u8_t *)&buffer[l], q->len);
            l = l + q->len;
        }
    }

    /* Release descriptors to DMA */
    /* Check if frame with multiple DMA buffer segments */
    if(DMA_RX_FRAME_infos->Seg_Count > 1)
    {
        DMARxNextDesc = DMA_RX_FRAME_infos->FS_Rx_Desc;
    }
    else
    {
        DMARxNextDesc = frame.descriptor;
    }

    /* Set Own bit in Rx descriptors: gives the buffers back to DMA */
    for(i = 0; i < DMA_RX_FRAME_infos->Seg_Count; i++)
    {
        DMARxNextDesc->Status = ETH_DMARxDesc_OWN;
        DMARxNextDesc = (ETH_DMADESCTypeDef *)(DMARxNextDesc->Buffer2NextDescAddr);
    }

    /* Clear Segment_Count */
    DMA_RX_FRAME_infos->Seg_Count = 0;

    /* When Rx Buffer unavailable flag is set: clear it and resume reception */
    if((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)
    {
        /* Clear RBUS ETHERNET DMA flag */
        ETH->DMASR = ETH_DMASR_RBUS;
        /* Resume DMA reception */
        ETH->DMARPDR = 0;
    }

    return p;
}

/**
 * This function should be called when a packet is ready to be read
 * from the interface. It uses the function low_level_input() that
 * should handle the actual reception of bytes from the network
 * interface. Then the type of the received packet is determined and
 * the appropriate input function is called.
 *
 * @param netif the lwip network interface structure for this ethernetif
 */
err_t ethernetif_input(struct netif *netif)
{
    err_t err;
    struct pbuf *p;
    /* move received packet into a new pbuf */
    p = low_level_input(netif);

    /* no packet could be read, silently ignore this */
    if(p == NULL)
    {
        return ERR_MEM;
    }

    /* entry point to the LwIP stack */
    err = netif->input(p, netif);

    if(err != ERR_OK)
    {
        LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
        pbuf_free(p);
        p = NULL;
    }

    return err;
}

/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t ethernetif_init(struct netif *netif)
{
    LWIP_ASSERT("netif != NULL", (netif != NULL));
#if LWIP_NETIF_HOSTNAME
    /* Initialize interface hostname */
    netif->hostname = (const char*)DTUName;
#endif /* LWIP_NETIF_HOSTNAME */
    netif->name[0] = IFNAME0;
    netif->name[1] = IFNAME1;
    /* We directly use etharp_output() here to save a function call.
     * You can instead declare your own function an call etharp_output()
     * from it if you have to do some checks before sending (e.g. if link
     * is available...) */
    netif->output = etharp_output;
    netif->linkoutput = low_level_output;
    /* initialize the hardware */
    low_level_init(netif);
    return ERR_OK;
}



